Multi language not working ...

This is a strange behaviour, dont't know if is front page module issue, but let's see:

I configure D6 with "Path prefix with language fallback", with default en, and pt as another language.

If I log in, both links work, /en/front_page and /pt/front_page, and everything is normal.

But in anonymous, the only url that works is or /pt
if i enter /en or /en/front_page or /pt/front_page it says page not found...

any ideas?
thks